The present invention relates to a gear train with a central wheel, at the circumference of which one or more pinions are arranged with are mounted in a gear case and which drive the central wheel or are driven by it. The position of the pinion serration or teeth relative to the central wheel serration or teeth is influenced through external adjusting forces.
Such gear trains are used, e.g. for multi-shaft compressors, in which overhung or cantilevered radial compressor stages are arranged on the pinion shafts, which run at different speeds to maintain an optimum volumetric rate of flow. The function of the central wheel of the gearing is, in combination with the pinion shafts, to establish the correct rpm transmission from the drive and at the same time a sufficiently large radial spacing between the rotors and the spiral housings surrounding the rotors. The central wheel is generally driven by a slowly running electric motor.
With the increasing diameter of the rotors and of the spiral housing, also larger diameters of the central wheel and, at constant rotational speed of the drive, also high circumferential speeds of the central wheel are necessary, which bring about increased mechanical friction losses in the correspondingly enlarged sliding bearings of the central wheel and ventilation losses at the end faces of the gear wheels in the gear case. This effect is intensified with increasing rotational speed of the drive, as for example, in steam turbine drives. It has therefore been proposed to transmit the driving power of the turbine to the central wheel through a pinion disposed on the circumference of the central wheel (French Pat. No. 1,318,232).
In U.S. Pat. No. 2,337,501, a hydraulic adaptation of the pinion shaft position in a spur gear transmission has been described.
In U.S. Pat. No. 3,160,025, an additional torque between the teeth of gears in engagement with one another is produced with permanent magnets.
In German OS No. 33 26 619, a uniform load distribution over the tooth width is brought about for a spur gear transmission with large tooth width by using drives controlled by transducers via signals.
From German OS No. 32 20 851 a magnet bearing with permanent magnets and adjustable support position is known.
In German AS No. 12 02 392 automatic electromagnetic centering of two rotors arranged coaxially one behind the other is described, but here the position of the axis cannot be influenced, as in the case with the known active magnet bearings.